Glycogen Depletion – Signs and Symptoms

In an earlier article we took a very deep look at what glycogen is, the benefits it can provide strength, power, and fitness athletes, and how you can maximize its ergogenic effects. Sometimes, however, an athlete/coach may not not be aware that of dropping or depleted glycogen levels, which can be a detrimental (and highly controllable) environment for optimal performance, strength, power, and muscle growth.

Therefore, in this article we will discuss common signs and symptoms of glycogen depletion so that coaches and athletes can monitor themselves closer and avoid depleting energy-rich stores of glycogen within muscle tissues.

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Feeling run-down and weak? You may be suffering from glycogen depletion

Signs and Symptom of Glycogen Depletion

Below are six (6) common signs and symptoms of glycogen depletion that coaches and athletes can use to determine if they’re at risk for glycogen depletion.

Decreased Strength and Power

Skeletal muscles rely heavily on stored muscle glycogen to fuel forceful and explosive muscle contractions. When lifting heavier weights (and even lighter weights for this matter), the body is primarily working anaerobically (without oxygen). Carbohydrates are necessary for the body to kickstart this metabolic process (as fats are oxidized via the Krebs Cycle, which also require carbohydrates), and without ample carbohydrates in the system the body will not be able to produce high amounts of energy to promote forceful muscle contractions. While there may be other factors that contribute to decreased strength and power, low muscle glycogen levels (glycogen depletion) can be responsible (in addition to lack of recovery).

Increased Rate of Perceived Exertion

Increase rate of perceived exertion (RPE) is often seen with athletes and lifters who are experiencing glycogen depletion. Typically, this will occur when an athlete perceives the normal workouts (might not necessarily be just one bad day, but a series of bad workouts) routine as noticeably harder than usual. This can obviously be due to a magnitude of factors, however increasing workloads, intensities, and need for recovery and restoration from hard training demands a greater emphasis on carbohydrate consumption and glycogen repletion.

Feeling of “Flatness” in Muscle Bellies

Muscle glycogen is stored in skeletal muscle, and along with that comes increased muscle volume due to mainly water being drawn into muscles. One way to judge whether or not you may be having glycogen depletion is to self-assess how the your muscles looks/feel compared to normal. A glycogen rich muscle often holds water, giving it a feeling of fullness and size (which can be a subjective measure nonetheless). If you are experiencing a feeling of flatness or depleted muscles (yes, as crazy as this sounds), it may be due to glycogen depletion.

Increase Weight Loss (Water) Overnight

In addition to feeling “flat”, you may notice large fluctuations of body weight while you sleep, which often suggest water loss. While this can be from other reasons, such as you cutting for a competition, it can also suggest that your muscle glycogen levels are dropping, which in turn has you lose water volume. This is often why many low-carb diets will produce significant decreases in weight loss in the very early stages of a diet. Conversely, this is also why some low-carb diet programs stall out, and often result in decreased muscle tissue, strength, and power (more from glycogen depletion than water loss).

Lack of Recovery

While recovery issues from strenuous exercise sessions and/or prolonged period of training can happen for many reasons, nutritional factors can play a significant role in one’s ability to recover. During hard training periods, muscles are asked to perform at higher intensities, greater volumes, and more often (generally). If an athlete fails to replenish muscle glycogen after every session, he/she may slowly diminish the amount of muscle glycogen they have on a daily basis, ultimately going into a depleted state. The solution is to replenish glycogen immediately (or even during) hard training sessions and throughout the day (process take longer than one day) to avoid this catabolic stage.

Decrease Exercise-Performance During Longer Workouts

While this can simply be due to muscle fatigue or the fact you have done a tough workout, it may also be due to glycogen depletion, which can set in 20-30 minutes into hard training sessions (assuming you came into the session with high levels of muscle glycogen). It is often for this reason that strength, power, fitness, and endurance athlete will supplement with carbohydrates (and proteins, often BCAAs) during training sessions so that they may keep their muscle glycogen levels high (which also triggers protein synthesis and decreases RPE).

Mike holds a Master's in Exercise Physiology and a Bachelor's in Exercise Science. Currently, Mike has been with BarBend since 2016, where he covers Olympic weightlifting, sports performance training, and functional fitness. He's a Certified Strength and Conditioning Specialist (CSCS) and is the Assistant Strength and Conditioning Coach at New York University, in which he works primarily with baseball, softball, track and field, cross country. Mike is also the Founder of J2FIT, a strength and conditioning brand in New York City that offers personal training, online programs for sports performance, and has an established USAW Olympic Weightlifting club. In his first two years writing with BarBend, Mike has published over 500+ articles related to strength and conditioning, Olympic weightlifting, strength development, and fitness. Mike’s passion for fitness, strength training, and athletics was inspired by his athletic career in both football and baseball, in which he developed a deep respect for the barbell, speed training, and the acquisition on muscle. Mike has extensive education and real-world experience in the realms of strength development, advanced sports conditioning, Olympic weightlifting, and human movement. He has a deep passion for Olympic weightlifting as well as functional fitness, old-school bodybuilding, and strength sports. Outside of the gym, Mike is an avid outdoorsman and traveller, who takes annual hunting and fishing trips to Canada and other parts of the Midwest, and has made it a personal goal of his to travel to one new country, every year (he has made it to 10 in the past 3 years). Lastly, Mike runs Rugged Self, which is dedicated to enjoying the finer things in life; like a nice glass of whiskey (and a medium to full-bodied cigar) after a hard day of squatting with great conversations with his close friends and family.

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